This invention relates generally to devices which are capable of detecting sources of electromagnetic radiation or the presence of electromagnetic fields and, more particularly, to an optical device which can be placed in the proximity of a weakly radiating source and which is capable of detecting electromagnetic radiation emanating from the source.
Whenever an electric charge oscillates or is accelerated, a disturbance characterzed by the existence of electric and magnetic fields propagates outward therefrom. Such a disturbance is generally referred to as electromagnetic waves. The range of frequencies of such electromagnetic waves is extremely large, ranging in frequency from approximately 10.sup.22 Hz for gamma rays emanating from radioactive nuclei to 0 Hz in the form of direct current emanating from batteries. In theory, any electromagnetic radiation can be detected by its heating effect. A method incorporating this effect can be used over the range from X-rays to radio waves. Ionization effects measured by cloud chambers, photographic emulsions, ionization chambers, and Geiger counters have been used in the gamma and X-ray regions. Direct photography can be used from the gamma ray to the infrared region. Fluorescence is effective in the X-ray and the ultraviolet ranges while bolometers, thermocouples, and other heat measuring devices are used chiefly in the infrared and microwave regions.
The present invention is primarily concerned with the detection of electromagnetic radiation or electromagnetic fields emanating from such electronic components as printed circuit boards and other individual electronic components such as integrated circuit packages. Heretofore, the detection of such electromagnetic radiation involved the use of detectors which included electrical wires which had to pass through the walls of electrical equipment incorporating such components therein. Unfortunately, the use of electrical conductors such as wires resulted in compromising the integrity of the electrical equipment and therefore such past electromagnetic detectors were less than desirable. In addition, the sensitivity of past detectors was unacceptable in many areas of use. Consequently, it would be extremely desirable to provide a sensitive electromagnetic radiation detector which also eliminated the use of wire connectors in their makeup.